Thermometer.



Patented July 4, 1911.

G H. W. E

A. ROESUH.

THERMOMETER.

APPLICATION FILED 11,119.27, 1911.

a T I COLUMBIA PLANOGRAPM co.. WASHINGTON. D. c.

*nog

ALFRED ROESCI-I, 0F NEW YORK, N. Y., ASSIGNOR TO CHARLES Ji TAGLIABUE,0F BROOKLYN, NEW YORK.

THERMOMETER.

Specification of Letters Patent.

Patented July 4, 1911.

To all whom '1125 may concern:

Be it known that I, ALFRED ItoEsoH, a citi- Zen of the United States,and a resident of the borough of Brooklyn, county of Kings, city andState of New York, have invented certain new land useful Improvements inThermometers, of which the following is a specification.

My invention relates to thermometers and more particularly tothermometers for taking the .temperature of baths of any kind,particularly oil baths and other baths of high temperature, of sand,gravel, metal and the like and has for its object to provide such aninstrument which at a glance, will give correct readings, either afterbeing totally immersed in the bath, or in contact throughout with themedium being measured, or when its bulb only has been immersed, or incontact with said medium, or when it has been immersed, or in contact upto certain predetermined points. Heretofore, if a thermometer was usedunder coni ditions other than those corresponding to total immersion orcontact, as in the case when the bulb only is immersed, or in contact orthe thermometer stem projects from the medium or emerges from the bathmore or less, it has been necessary to apply a correction for emergentstem, in order to obtain a correct reading. This is due to the fact thatthe emergent stem and mercury contained therein may be at a temperaturedifferent from that of the medium, the temperature of which isbeing'measured so that if the thermometer were properly calibrated fortotal immersion or contact, and then used only with the bulb immersionor contact the point reached by the mercury thread in this last instancewould not correctly indicate the temperature of the bath or othermedium. To obtain a correct reading under those conditions made itnecessary to carry out mathematical formula, which ofttimes were complexand many times incapable of being computed by the person using thethermometer.

rIhe particular object of my invention is to overcome this diiculty bymaking the mathematical vcomputations for projecting or emergent stemcorrection unnecessary and to obtain a correct reading under practicallyall conditions at a glance. To this end I provide my improvedthermometer with a number of scales, each properly calibrated and markedfor its particular purpose, that is, total immersion or contact, bulbimmersion or contact, or immersion 0r contact of a given length of stem.

My invention will be fully described hereinafter and the features ofnovelty will bepointed out in the appended claims.

Reference is to be had to the accompanying drawings in which* Figure lis an elevation of my improved thermometer and Fig. 2 is a diagrammaticview of three scales applied thereto in the specific form illustrated.

In the. drawings A represents the thermometer stem, B the mercury bulband C the mercury thread. In the particular and specific formof myinvention illustrated in the drawings, I have shown the stem A providedwith three scales, a total immersion or contact scale D, a bulbimmersion or contact scale E and a four inch immersion or contact scaleF. It will, of course, be understood that this is only an illustrationand that more scales may be provided for different degrees of immersionor contact, or only the two scales, that is, total immersion or contactand bulb immersion or contact produced on the stem. The two last namedscales being the most extensively used, will usually be sufficient.

If the thermometer is totally immersed in or in contact with the mediumwhose temperature is being measured, all parts of the instrument and themercury will be subjected to the same temperature so that the mercurywill be expanded to a maximum degree and will thus indicate thetemperature correctly on the scale D, which is graduated for thispurpose. If now the bulb B is only immersed in or in contact with themedium, the said bulb and the mercury therein will be subjected to thetemperature of said medium while the stem A will be subjected to thesurrounding temperature which may be considerably lower than that of themedium being measured. As the mercury rises in the stem a graduallyincreasing length thereof becomes alfected by the said surrounding lowertemperature so that the relative degree of expansion changes as themercury continues to rise. For a given temperature, therefore, themercury will not rise as high as is the case when the thermometer isimmersed, or entirely in contact with the medium, so that if only onescale were promercury therein When the bulb only is immersed or incontact Would be, for instance, 664 While the real temperature Would be700. To obtain the correct temperature under such conditions, it Wouldthus be necessary to resort to a mathematical calculation for emergentor projecting stem correction. To avoidthis, I provide the scale E whichis graduated to correctly indicate the temperature if the bulb only isimmersed in or in contact With the medium under investigation.Similarly, if, for instance, four inches of the instrument is immersed,or in contact With said medium a greater portion thereof and a greateramount of mercury will be subjected to the temperature of the mediumbeing measured and less to the surrounding loWer temperature than is thecase When the bulb only is immersed or in contact. For a giventemperature, the mercury Will, therefore, rise to a higher pointon thestem than When the bulb only is immersed, or in contact With the medium,but Will not rise as high as is the case when the total immersion orcontact of the instrument takes place. In other Words, an intermediatepoint or condition is reached.

It Will readily be seen that even if the bulb immersion or contact scaleE Were provided in addition to the total immersion or contact scale D, acorrect reading With four inches of the stem immersed or in contactcould not be obtained from either scale Without a mathematicalcalculation. To avoid this I provide a scale F properly graduated togive a correct reading When four inches of the stem project into orcontactvvvith the bath or other medium. Similarly additional scales maybe provided properly graduated for different degrees of immersion orcontact to cover all conditions which may arise. Each scale ispreferably marked as shovvn at G, H and I respectively to indicate itsrespective function, so that at a glance the proper and correcttemperature may be ascertained by simply referring to the scalegraduated for the special condition under which the thermometer is beingused. Furthermore, each scale may be compared with the other for testingpurposes. That is, by calculating, for instance, hoW high the mercuryshould arise on the total immersion or contact scale at a giventemperature when only the bulb is immersed, or in contact With themedium, and then immersing or contacting the bulb only and noticing theresult it is easy, by comparing the tvvo scales, to find out if the bulbimmersion or contact scale is correct. It is thus a simple matter toascertain if these tvvo scales and likewise any additional scales Whichmay be provided, are in accord.

It is to be understood that When speakingv of total immersion or contactthroughout either in the description or in the claims, I mean totalimmersion or contact throughout up to the degree of temperature of themedium of investigation. That is if the bath or other medium has atemperature of 300, the thermometer is considered totally immersed or incontact throughout When all portions thereof up to the 3000 indicationare immersed or in contact. The claims are therefore to be construedaccordingly.

Various changes in the specic form illustrated and described may be madeWithin the scope of the claims Without departing from the spirit of myinvention.

I claim as my invention:

l. In a thermometer for measuring temperature, an eXpansible indicatingmedium, and a plurality of scales produced on said thermometer, eachscale being graduated in proportion to the expansibility of theindicating medium under a` definite extent oi contact With thermediumWhose temperature is being measured, such extent for each scale beingdifferent from that of the other scales.

2. Ina thermometer for measuring temperature, an expans'ible indicatingmedium, a plurality of scales produced on said thermometer, one scalebeing graduated to indicate the temperature When the thermometer is incontact throughout vvith the medium Whose temperature is being measured,and another scale being graduated to indicate the temperature when thebulb only is in contact with said medium.

3. In a thermometer for measuring temperature, an eXpansible indicatingmedium, a plurality of scales produced on said thermometer, one scalebeing graduated to indicate the temperature when the thermometer is incontact throughout with the medium Whose temperature is being measured,a second scale being graduated to indicate the temperature when the bulbonly is in contact With said medium and a thirdY scale being graduatedto indicate the temperature whenk the thermometer contacts with Vsaidmedium to a point intermediate of the thermometer ends.

In testimony vvhereof I have hereunto set my hand in the presence oftvvo subscribing Witnesses.

ALFRED ROESCH. Witnesses i l JOHN A. KEHLENBEGK, LoUIs ALEXANDER.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

